Using smart phones, Matthew A. Killingsworth and Daniel T. Gilbert of Harvard University collected a large sample of experiences and associated happiness. They also measured “mind wandering.” Their database currently contains nearly a quarter million samples from about five thousand people from eighty-three different countries who range in age from eighteen to eighty-eight and who collectively represent every one of eighty-six major occupational categories. Their findings confirm what had been found previously: happiness is high during sex, exercise, or socializing, or while the mind is focused on the here and now, and low during commuting or while the mind is wandering.